Decorative laminates are widely employed in the building industry for use as counter tops, kitchen and bathroom work surfaces, wall panelings, floors, cabinets, partitions and doors. Because they are generally more durable than wood and provide an attractive appearance, decorative laminates are also popular in the furniture industry, primarily as tops for furniture such as tables and desks.
The extensive use of these decorative laminates is primarily due to their low cost, impact and abrasion resistance, durability, clarity, and their resistance to heat, ultraviolet light and mild chemicals.
Decorative laminates are conventionally made from a core or body comprising a plurality of sheets of a fibrous material such as unbleached kraft paper which can be impregnated with a thermosetting resin. A decorative sheet also known as a decor sheet can be mounted on top of the core to hide or disguise the underlying core. The decor sheet typically comprises a fibrous sheet having either a design printed on it or it may have pigments dispersed therethrough to provide a solid color decor sheet. The decor sheet is generally made of high quality cellulosic fiber impregnated with a thermosetting condensation resin such as melamine-formaldehyde resin. Another sheet known as an overlay is commonly used as a protective covering for the decor sheet. Examples of such overlays are described in U.S. Pat. No. 4,505,974 and Canadian Patent No. 990,632.
Typically the decor sheet is a single layer sheet which exhibits good hiding power, surface durability and gloss. Generally, these properties are achieved by adding an opacifying pigment such as titanium dioxide to the paper furnish for the decor sheet to provide a controlled level of opacity and saturating the decor sheet with appropriate amounts of resin to insure that adequate resin is available on the surface of the sheet to provide durability.
The addition of pigment and resin to the decor sheet have opposing effects on the opacity of the sheet. Reducing the resin concentration in the decor sheet tends to improve the hiding power, but lowers the gloss and surface durability. Increasing the resin concentration has the effect of lowering the hiding power of the decor sheet while increasing gloss and surface durability. Thus, the addition of higher amounts of resin to improve durability may require that additional pigment such as TiO.sub.2 be incorporated in the sheet to compensate for loss of opacity. Such a sheet does not efficiently utilize either TiO.sub.2 or saturating resin. The large amounts of resin and TiO.sub.2 employed in such decorative sheets are unattractive from an economic point of view particularly with respect to TiO.sub.2 which is very expensive.
Thus, it would be desirable to provide an economical decor sheet which employs reduced amounts of both resin and TiO.sub.2 and which exhibits good hiding power without sacrificing desirable surface durability properties and gloss to decorative laminates. The present invention provides such a decor sheet.